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Two tidbits from New Zealand:
– A recent survey of volcanoes in the Kermadec Arc north of New Zealand suggest that there is abundant – and recent – undersea volcanism. Scientists from University of Washington (one of my former homes) and Southhampton University (UK) explored a number of submarines volcanoes including Rumble II West, Rumble III and Brothers, which are all located along the same arc of volcanoes as New Zealand’s own White Island and Mt. Edgecumbe. What they found was a change in the shape of Rumble III (1.4 km below the sea surface) since the last survey in 2007 – the summit crater has been filled and the height of the summit cone is almost 100 m shorter! Sounds like that would have been a significant eruption for that sort of physiographic changes to the volcanic edifice. Previous to this, the last known eruption at Rumble III was in 1986, but the only known eruptions are based on hydrophone evidence. They also found abundant “black smokers” on Brothers Volcano. The map of Rumble II West (above) also shows what appears to be a caldera-like feature with a new cone growing in the center. Studies like this always make me wonder how many eruptions occur under the surface of the ocean that go unnoticed.
– If you’re into historical accounts of volcanic eruptions (and who isn’t?), you might enjoy the snippet posted in the Otaga Daily Times from 1909 entitled “Little to fear from Ngauruhoe’s eruption”. Mt. Ngauruhoe (which is really just the youngest vent of Mt. Tongariro) erupted 100 years ago on March 11 (see above), the original articles reports that the eruption was “the finest seen in New Zealand for years.” The eruption in 1909 was one of many of the volcano in the 20th century, explosive eruptions of ash and debris with moderate intensity (VEI 2).//Below are the comments from the original posting of this article.
doug Says:
March 12, 2009 at 1:33 am e
given the relative proportion of the earth that is covered by water compared to land and the various plate boundaries, should one assume that there are many more underwater volcanoes than those that reach above sea level (continental and island arc)?
gg Says:
March 12, 2009 at 4:50 am e
Do tell, Dr. K! Just want to say that I check the world earthquakes and volcanoes. We have underwater vents in Canada, even. If it’s on the Ring of Fire, and in water, I’d guess there’s a pretty good chance of underwater volcanoes.
New Zealand undersea volcanism at the Eruptions blog « The Volcanism Blog Says:
March 12, 2009 at 8:13 am e
[…] New Zealand undersea volcanism at the Eruptions blog 12 March 2009 Posted by volcanism in New Zealand, current research, geoscience, submarine volcanism. Tags: Kermadec Arc, New Zealand, undersea volcanism, volcano research trackback Dr Klemetti has an interesting post at his Eruptions blog today on undersea volcanism in the Kermadec Arc, north of New Zealand. A study by the University of Southampton and the University of Washington found evidence of a high level of volcanic activity in this area, with the delightfully-named Rumble III volcano having apparently filled in its crater and lost 100m in height since 2007. Eruptions has all the information and relevant links: Volcanoes old and new in New Zealand. […]
Bruce Says:
March 12, 2009 at 1:54 pm e
Wow! that’s almost like Indonesia!
Erik, I just had a thought, do you think the volume of rhyolite produced by the TVZ has something to do with the fact that the plate boundary is actually dissecting (or trying to) the submerged continent of Zealandia? I read one report a couple of years ago that theorized that melt from the plate boundary was being transferred north from the south of the North Island to be pooled under Taupo .. (this was also to explain the absence of volcanism south of Ruapehu) but couldn’t the volume of rhyolite simply be a product of the thickness of the Zealandia continent itself? Does anyone know of any other regions where plate boundaries are actually dissecting a continent (and no, I don’t mean rift scenarios).. Is there any comparable volcanism?
Thomas Donlon Says:
March 13, 2009 at 8:26 am e
Erik,
I’d be interested to link the location of these volcanoes with current earthquakes so that maybe we could get a sense ahead of time which volcanoes may continue to be active – or be in danger of erupting.
Now are all these volcanoes that you are talking about underwater? And how close are they to breaking through to the surface and how dangerous would that be? So if any breaks through to the surface would it pose any threat for worldwide climate? I am thinking anything that might be Pinatubo size or larger. We have gone a number of months with a dearth of meaningful sunspot activity. Even the occasional sunspot now is often tied in with the last sunspot cycle. A few degrees cooler – like what Pinatubo generated on top of a presently cooling off earth may translate into meaningful or substantial cooling.
Bruce Stout Says:
March 13, 2009 at 11:23 am e
To Thomas!
first thanks for your feedback on my post the other day.
The best way to trace the correlation between the earthquakes and these volcanoes is probably still via the USGS earthquakes site and then when one happens click on the link to Google Earth. I know there are plans to put the seabed into Google earth but I haven’t seen anything yet.
There has been a lot of earthquake activity along the Kermadec trench but from what I have seen most of it has been in the subducting Pacific plate rather than volcano related.
I’d like to see comparable studies for up near Tonga because they have positively huge rates of subduction up there and all that material must result in some volcanism someday, me thinks.
NZ is kind of strange because the axis of subduction flips completely along the Southern Alps and this seems to be holding up plate movement. The TVZ is actually a zone of attenuated crust (ie. extensional) like a rift zone but with a subducting plate underneath it providing the oomph. As far as I know this scenario extends up into the Havre trough NNE of NZ:http://www.teara.govt.nz/EarthSeaAndSky/OceanStudyAndConservation/SeaFloorGeology/5/ENZ-Resources/Standard/2/en

Folks have been suggesting that life on Earth started near volcanic vents for a long time now (and of course, some people don’t buy it). Whether or not life sprung forth near hydrothermal vents, undersea black smokers or from the head of Zeus, it doesn’t really change the fact that we find organisms living in these places today, expanding what we might consider “habitable” by leaps and bounds. Case and point, researchers from CU-Boulder have recently found a community of micro-organisms happily living near the summit of Volcán Socompa (above) in Chile in the hydrothermal vents. Now, having done field work in the high Andes of Chile (at Volcán Aucanquilcha – say that three times fast), I can attest to the fact that it is as close to working on Mars as you might be able to get on Earth – dry, desolution, mostly lifeless, extreme day/night temperature variations, thin air, the whole nine yards. So, to find these communities shows just how hardy life can be when presented with challenges.
One interesting question not brought up in the article is how quickly might these communities develop. Socompa was last known to have erupted in 5250 B.C. (most likely). This might limit the amount of time for these micro-organisms to take a foothold at the summit of the volcano to at most ~7,000 years. This seems like a pretty reasonable time for life to reemerge after an eruption – the question would be from where did it arrive in a place as desolate as the high Andes of Chile after the eruption. Of course, this also begs the question of whether life like this could exist of Mars, but that is question best left untouched by me. To me, this is just another example of how no matter how destruction we think volcanoes are, life just keeps on coming back for more.{Hat tip to reader Thomas Donlon for pointing this out to me.}

Count this as your mini-update for Redoubt, with the news being no news. Even AVO seems a little bored with Redoubt lately (not to say they aren’t watching it as vigilantly as ever) as their last three updates have been exactly the same:

Redoubt volcano has not erupted. Seismicity is low, but above background levels and consists mainly of small discrete earthquakes. Night has fallen and no image is visible in the webcam.

The Redoubt watch is now been going for well over a month and this is how quickly things can change when monitoring volcanoes. The headline in my volcano RSS, when I saw it said:

“Redoubt quiets after weeks of activity, though eruption still possible”

By the time I clicked on the link, the headline for the KTUU TV article became:

“Redoubt steaming at strongest level, seismic activity calms”

The seismic event refered to happened yesterday afternoon (Alaska time) and the volcano rumbled for about an hour, getting picked up by seismometers all around the Cook Inlet. They also mention that steam vents on the volcano were the most vigorous as has been seen so far. John Power from AVO did temper the expectations of activity:

“We do feel that the most likely outcome of the current activity of level will be a eruption at some point, although it is still always a possibility that it could die away…”

Currently, Redoubt seems to have quieted back down according to the latest report from AVO. The watch marches on.

The people who remain in Chaiten face the potential for a devasting pyroclastic flow, so says Jorge Muñoz of the SERNAGEOMIN in Chile. The volcano is still producing large ash columns on Tuesday and a flyover of the dome forming inside the caldera has lead to the concern that a collapse on a larger scale than those seen last week could wipe out the town for good.
The government hopes news like this from volcanologists might convince the last remaining residents of Chaiten to leave, but no indication of this has come to pass. In fact, things sound like they’re getting heated in the fight over the town of Chaiten. The Minister of Government Affairs had this to say to the lawyers for the remaining residents:

“I think that up until now, we have been quite convincing, but to say that the problem is to unblock the river (…) Why don’t we back up a bit? Why is the river overflowing? Because the volcano is exploding, that’s why!”

It gets even uglier here from the Undersecretary of the Interior. It seems that both sides are digging in the heels, so to speak.

Jonathan Castro has reminded me that I need a refresher on the proper terminology for ash columns related to volcanic eruptions. It is very easy to start mincing words and using them inappropriately – and that is the sort of sloppy reporting and discussion I am trying to avoid.
So, to refresh my (and our) memory on ash clouds and how to classify them, we can go back to one of the indispensable textbooks on volcanology, Cas and Wright’s Volcanic Successions. The classification scheme they provide is summarized in the figure above. It shows the heights of various eruption columns and the relationship between types of eruptions and their “explosiveness”. Jonathan is likely correct in classifying this eruption in the vulcanian range (<20 km ash column), especially if it was driven by explosions in the dome. If anything, Chaiten’s activity today could be sub-plinian, but a true plinian eruption requires a taller ash column height and higher levels of explosivity.UPDATE 2/20/2009: Here is a link to an article that talks about the processes that go along with each eruptive style. Remember, the ash column nomenclature is not solely dependent on height, but also process and composition. {Thanks to Boris for reminding me to emphasize this.}

UPDATE 2/19/2009 9:45 AM:Well, it seems that my hunch was at least partially right. Reuters (and Paula Narvaez, special envoy to the Chilean president) is calling the eruption as result of “what appeared to be a partial collapse of its cone.” So, we might have seen the oversteepening of the dome growing in the Chaiten caldera that lead to a collapse, producing (likely) a pyroclastic flow and either an accompanying plinian eruption as the pressure was released or an ash column associated with the pyroclastic flow itself. Now, I might not take Reuters word for it, but it makes sense considering the suddenness of the event.10:00 AM:More details for Reuters, including the ominous “Our security team have observed an increase in the size of a column of ash and smoke, with a deformation to one side” from the Deputy Interior Minister. My guess is he is referring to deformation on the ash column, not the volcano.4:00 PM: From a Newsday article, just some more details on the ash dispersal: “On Thursday, increased seismic activity was reported and ash fell 100 miles (160 kilometers) away in Futaleufu.”
—Eruptions reader Brian Owens has pointed out that fellow volcano follower, the Volcanism Blog, is reporting that Chaiten is experience a major rejuvenation today.
Sure enough, the Associated Press also reporting that an explosion has occurred in the main dome of Chaiten that has been built since last May and that material is moving downslope from the explosion. There is no clear word what type of volcanigenic material this might be – pyroclastic flow, lahars, avalanche – but there is a major fear that it could block the river and cause flooding in the town of Chaiten. The few citizens left in the area are being evacuated. The Patagonia Times adds that the eruption started around 11 A.M. (local time) and ash has spread across much of the region.
From what I can gather, this seems like it might have been either a dome collapse that was quickly followed by an explosion (possibly caused by the release of pressure from the collapse) or some “burp” of gas-rich magma erupting. The reports of “a massive column of ash” are interesting as this could suggest a true new flux of magma, but it is hard to tell at this point how widespread is the ash and how tall the column might be. At this point, it is all conjecture, but it sounds like Chaiten might be making a comeback. The questions woulds be how big and for how long.
I’ll update as we find out more …

Redoubt Volcano has not erupted. Elevated seismicity is continuing, dominated by ongoing volcanic tremor and occasional small earthquakes. A storm system is moving across the Redoubt area at present, which will make for poor viewing conditions today. Associated winds are causing a small increase in seismic amplitudes on some seismic stations. AVO continues to monitor Redoubt 24 hours a day.

So, don’t get too excited about slightly elevated apparent seismicity over the weekend (and note, with the poor visibility, this would be a great weekend for Redoubt to decide to erupt).

Is the volcano just toying with us?
After yesterday’s steam plume (woo.), Redoubt was relatively normal today, albeit still at the heightened state of readiness. However, the steam plume has waned today compared to yesterday.
Now, whether this is actually a signal that the magma is not rising up into the volcano as rapidly as before or this is just the quiet before the storm is anyone’s guess. This very well could be like the 2004-08 Saint Helens episode that ended up being fairly benign with only passive eruption (if there is such a thing) of dome material (hat tip to Boris for bringing up this idea yesterday) rather than any plinian-style eruption like the 1989-90 Redoubt eruption. Stay tuned!